Well I live in Wales and adhere to Rent Smart Wales . They stipulate that by 14days it should be collected or landlord is entitled to dispose of any possessions left behind . Has your ex tenant given any reason for not collecting . Sometimes they leave stuff they no longer want .To cover yourself you need to contact and give time to be collected .

For a full discussion of Abandoned Goods - see https://www.PossessionFriend.uk Landlord Advice - Abandonded goods. There is a downloadable Torts Notice and Practical advice on dealing with different types and values of goods left.